The invention relates to a device for turning over a length or sheet of flexible material, such as a length of textile fabric.
Such devices are known; however, they all have the drawback that they are not suitable for picking up panels of textile material already cut to a particular shape, are complicatd or do not make precise positioning possible. In addition, they are generally slow.
Thus, from GB-A-1,128,349, a device is known by means of which lengths of textile fabric can be taken up from a pile by the edges of the length being clamped between a clamping plate and a roller covered with friction material, which length is then stretched taut by the opposite rotation of the rollers applied to the edges of the length to be taken up and is separated from the pile, after which the extricated length is raised up by means of said clamping means applied to the edges and transported to a conveyor belt where the length is released so that it lands on the conveyor belt. If said release takes place by both edges being set free simultaneously, the length falls onto the conveyor belt in the original position. If, on approaching the conveyor belt, the edge situated nearest at that instant is released, the latter will arrive first on the conveyor belt so that, as the other edge which is still clamped travels further, the length is turned over. The tautening of the length and the application of friction material thereto may result in damage in the case of many textile materials to be processed. The laying down takes place inaccurately, in particular if turning over has to take place. The device is complicated and operates slowly.
From DE-A-1,936,351, a device is known for turning over a length in which clamping means are applied to one edge of the length, raise said edge and then bring about the turning over by performing a horizontal movement over the support, the clamping being released at the end of said horizontal movement.
In ready-made clothing workshops, the textile material originating from a roll is deposited on long tables by means of a device with zig-zag movement in a manner such that a pile is produced. As a result of said zig-zag movement, the layers of textile material lie on top of each other with the rear sides or with the front sides of the textile material against each other in turn. From these piles, panels are cut which have to be fastened to each other by means of sewing machines to manufacture garments. The panels cut from the piles are picked up one by one with a device suitable for this purpose, an example of which is to be found in the non-prior-published Dutch Patent Application 8502400.
These panels removed from the pile have alternately to be turned over or not turned over before an operation can be carried out. The same requirement for alternately turning panels over or not turning them over arises if the panels are being processed with left-right symmetry.
If the textile material is not heaped up in a zig-zag manner and if the panels are not processed with left-right symmetry, the requirement may exist for all the panels in a pile to have to be turned over. This occurs when panels in two piles are combined. For the purpose of the further processing, the panels in piles generally have a number which corresponds to the ply of textile fabric for which the panel has been cut. If a pile is turned over as a whole and the different panels of two piles are combined, then the panels have a different number, which should be avoided in view of the possible colour differences in the textile fabric. In such cases, all the panels in a pile are turned over one by one.
Even if panels are intended to be cut in single ply, it may be necessary for panels to be turned over for the purpose of further processing.
For turning over, speed and accuracy are a first requirement in particular if it is intended to automate the manufacture of garments as much as possible. A problem in this connection is that the cut-out panels have shapes which differ from a regular shape such as a rectangle. Another problem is that the lengths which are processed successively are difficult to handle due to their large flexibility.
The problem may also arise that the lengths have different characteristics.
The object of the invention is therefore to provide a device with which it is possible to pick up a panel of any shape rapidly, turn it over and lay it down precisely in the place where that is necessary.
A further object is to provide a device which can be used universally regardless of the thickness and/or material characteristics.